Initial product adaptable to serve as a garment and its method of manufacturing

ABSTRACT

An initial product ( 10 ) adaptable to form a garment such as a diaper, training pant, pull-up diaper, adult incontinence pant and diaper holder. The initial product includes a chassis ( 14 ) for receiving the absorbent structure. The chassis includes a first lateral margin ( 20 ) and a second lateral margin ( 22 ). The first and second lateral margins are joined to a central structure ( 24 ) along a first line of joinder ( 26 ) and a second line of joinder ( 28 ), respectively, the first and second lines of joinder extending substantially parallel to the longitudinal axis. The first and second lateral margins have a first end region ( 44 ), a second end region ( 46 ) and a central region ( 48 ). The first and second lateral margins ( 20, 22 ) comprise a material ( 51 ) which is elastically extensible in at least the longitudinal direction in the central region ( 48 ). Lateral edges ( 40, 42 ) of the lateral margins are provided by third and fourth strips ( 76, 78 ) of substantially inelastic material. A method of manufacturing an initial product is also disclosed.

TECHNICAL FIELD

The present invention relates to an initial product adaptable to serveas a garment for receiving an absorbent structure, the garment beingintended to be worn around the waist of a user. Such garments aretypically known as absorbent articles and include, for example, childand adult diapers, training pants, pull-up diapers, adult incontinencepants, swim pants and diaper holders for receiving an absorbent insert.The invention further relates to a method of manufacturing such aninitial product.

BACKGROUND OF THE INVENTION

As well as good absorptive properties, primary requirements of absorbentarticles are good fit and comfort coupled with the need to preventleakage of any received bodily waste. To this effect, contemporaryabsorbent articles are provided with elastically extensible regionsaround the leg openings to thereby create a gusset around each leg whenthe article is worn. Typically, the elastically extensible regions arecreated by applying elastic threads under tension to a substrate andaffixing the elastic threads in a stretched condition to the substrate.When the tension is released, the elastic threads contract and gatherthe substrate. It is also known to provide waist portions of suchabsorbent articles with elastically extensible regions to therebyimprove the fit of the article to the user. Again, such regions may becreated by the provision of elastic threads or, alternatively, elasticstrips.

Similarly, the fit of pull-up type garments is enhanced if side panelregions are made from elastically extensible material.

In an attempt to improve the dynamic fit of an absorbent article, it isknown from U.S. Pat. No. 5,899,895 to provide an absorbent article witha single piece of extensible material which is folded such that theextensible material extends throughout both side panels, the waistregion and at least a portion of the crotch region. By suitable folding,the direction of extensibility of the material can be determined suchthat the material is extensible in the longitudinal direction of thearticle in the crotch region and in the transverse direction in thewaist region. However, it is not apparent how such folding can becarried out at high production speeds.

Although many contemporary absorbent articles provide adequate fit andcomfort, they demand complicated methods of manufacture. For example,the elastification of regions by means of elastic threads requires theprovision of a plurality of threads and machinery which is able to applythe threads in a tensioned state to absorbent articles at highproduction speeds. The threads are invariably affixed to the absorbentarticles by means of adhesive, something which is potentially messy andwhich inhibits the breathability of the finished article.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide an initialproduct, i.e. a product which may exist in a temporary state (sometimesreferred to as an “intermediate product”), which itself may serve as agarment or which, after subsequent operations, may serve as a garmentfor receiving an absorbent structure, which initial product includescomponents which facilitate the mass production of such products.

To this effect, in accordance with the present invention there isprovided an initial product adaptable to serve as a garment forreceiving an absorbent structure, the garment being intended to be wornaround the waist of a user. The initial product comprises a chassis forreceiving the absorbent structure, with the chassis extending in alongitudinal direction about a longitudinal axis (L) dividing thechassis into a first lateral half and a second lateral half. The firstlateral half comprises a first lateral margin and the second lateralhalf comprises a second lateral margin. The first and second lateralmargins are joined to a central structure along a first line of joinderand a second line of joinder, respectively, with the first and secondlines of joinder extending substantially parallel to the longitudinalaxis (L). The chassis further extends in a transverse direction about atransverse axis (T) dividing the chassis into a first end and a secondend. The chassis is delimited by a periphery comprising a first end edgeat the first end and a second end edge at the second end, the first andsecond end edges extending substantially parallel to the transverse axis(T). The periphery further comprises a first lateral edge of the firstlateral margin and a second lateral edge of the second lateral margin,the first and second lateral margins having a first end region extendingfrom the first end edge, a second end region extending from the secondend edge and a central region extending between the first and second endregions. The first and second lateral margins comprise a first strip anda second strip, respectively, of elastic material extending from thefirst end edge to the second end edge, which material is elasticallyextensible in at least the longitudinal direction in at least a portionof the central region. The first lateral edge of the first lateralmargin is provided by a third strip of substantially inelastic materialjoined to the first strip of elastic material along a third line ofjoinder and the second lateral edge of the second lateral margin isprovided by a fourth strip of substantially inelastic material joined tothe second strip of elastic material along a fourth line of joinder, thethird and fourth lines of joinder extending substantially parallel tothe longitudinal axis (L).

Since, in accordance with the invention, the first and second lateraledges of the first and second lateral margins are provided by strips ofsubstantially inelastic material, these strips serve to support thefirst and second strips of elastic material during the manufacturingprocess. This implies increased control over the manufacturing process.

In one embodiment of the invention, the first and second lateral marginsfurther comprise fifth and sixth strips, respectively, of substantiallyinelastic material. The fifth and sixth strips can be arranged to serveas standing gathers when the initial product is in the form of agarment.

In a further embodiment, the elastic material of the first and secondstrips is elastically extensible in at least one of the first and secondend regions in at least the transverse direction. Thus, the first andsecond lateral margins comprise a material which is elasticallyextensible in different directions in different regions to therebyprovide the requisite fit and protection against leakage. Furthermore,the material which is elastically extensible may be substantiallyhomogenous such that its elasticity is not dependent on adhesive beingapplied to the lateral margins during the assembly process of theinitial product.

In one embodiment of the invention, the elastic extensibility in thelongitudinal direction of the material in the central region of thefirst and second strips is at least 100% greater than the elasticextensibility in the transverse direction of the material in the firstand/or second end regions. The elastic extensibility in the longitudinaldirection in the central region may be from 90% to 350%, preferably from150% to 300% and most preferably from 200% to 250%.

Advantageously, the material is elastically extensible in the transversedirection in both end regions.

In a preferred embodiment, the elastic material of the first and secondlateral margins is elastically extensible in both the transverse and thelongitudinal directions in one or more of the central region and firstand second end regions.

The invention further relates to a method of manufacturing an initialproduct adaptable to serve as a garment for receiving an absorbentstructure, the garment being intended to be worn around the waist of auser, in which the initial product comprises a chassis for receiving theabsorbent structure. The chassis comprises a central structurecomprising a topsheet layer and a backsheet layer, as well as first andsecond lateral margins joined to the central structure along first andsecond lines of joinder, respectively. The method comprises the stepsof:

-   -   providing first and second strips of material which is or is to        be made elastically extensible in at least the machine        direction, the first and second strips serving as first and        second strips of elastic material of the first and second        lateral margins of the initial product;    -   feeding the first and second strips under varying tension        towards a first mating station via variable speed rollers;    -   providing third and fourth strips of substantially inelastic        material for constituting first and second lateral edges of the        initial product and feeding the third and fourth strips to the        first mating station;    -   joining the third and fourth strips to the first and second        strips at the first mating station by means of third and fourth        lines of joinder to produce a pair of initial united structures;    -   advancing the pair of initial united structures to a second        mating station;    -   providing at least one component of the central structure and        feeding the at least one component towards the second mating        station, and    -   joining the at least one component to the pair of initial united        structures at the second mating station by means of the first        and second lines of joinder to produce a subsequent united        structure.

The reference in the method claims to the first and second strips ofmaterial which is or is to be made elastically extensible in at leastthe machine direction implies that the material may be initiallysupplied in an elastically extensible state or may subsequently betreated so as to attain that state.

Further advantageous embodiments of the initial product and its methodof manufacture are detailed in the dependent claims appended hereto.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be described in greater detail in the following byway of example only with reference to various non-limiting embodimentsas depicted in the annexed drawings, in which

FIG. 1 is a schematic plan view of an initial product in accordance withone embodiment of the present invention in a flat, uncontracted state asseen from the body facing side;

FIG. 2 is a schematic sectional view along line II-II of FIG. 1;

FIG. 3 is a schematic sectional view along the transverse axis of aninitial product in accordance with one embodiment of the invention;

FIG. 4 is a schematic representation of a method for producing aninitial product of the present invention;

FIG. 5 is a schematic illustration of test equipment used to testelastic properties of material, and

FIG. 6 is a graph of force plotted against extension and illustratinghow elastic properties are to be determined.

DETAILED DESCRIPTION OF THE INVENTION

The invention will be described in further detail in the following withreference to the drawings in which reference number 10 generally denotesan initial product in accordance with the present invention.

With particular reference to FIG. 1, there is schematically shown aninitial product 10 adapted to receive an absorbent structure 12. As willbe described in the following, the initial product is adaptable to forma garment. In use, the garment is intended to be worn around the waistof a user. As illustrated in FIG. 1, for clarity reasons the initialproduct 10 is show in a laid-flat, uncontracted state. Although notillustrated, it will be understood that, when completed, the garment isprovided with suitable fastening means to allow the garment to befastened around the waist of a user.

The initial product 10 comprises a chassis 14 for receiving theabsorbent structure 12. In this respect, it is to be noted that theabsorbent structure 12 may either be integrally manufactured with thechassis to thereby form a unitary product, or the chassis may be adaptedto receive a replaceable absorbent structure once the chassis has beenmanufactured. Such adaptation generally includes the provision of apocket in the crotch region of the chassis into which a replaceableabsorbent structure may be slid. The latter type of garment is generallyreferred to as a diaper holder.

The chassis 14 extends in a longitudinal direction about a longitudinalaxis L which divides the chassis into a first lateral half 16 and asecond lateral half 18. The first lateral half comprises a first lateralmargin 20 and the second lateral half comprises a second lateral margin22. The first and second lateral margins are joined in manner which willbe explained later to a central structure 24 along a first line ofjoinder 26 and a second line of joinder 28, respectively. The first andsecond lines of joinder extend substantially parallel to thelongitudinal axis L. In this respect, the expression “substantiallyparallel” means any direction having a longitudinal component whichpermits the first and second lateral margins to be joined to the centralstructure during manufacture in the machine direction. The lines ofjoinder 26, 28 may be continuous or intermittent and may be formed inany conventional manner, such as by ultrasonic welding or usingadhesive.

The chassis 14 further extends in a transverse direction about atransverse axis T which divides the chassis into a first end 30 and asecond end 32. The chassis is delimited by a periphery 34 comprising afirst end edge 36 at the first end 30 and a second end edge 38 at thesecond end 32. Thus, the first and second end edges 36 and 38 extendsubstantially parallel to the transverse axis T and generally define awaist opening when the completed garment is fastened around the waist ofa wearer. The periphery 34 further comprises a first lateral edge 40 ofthe first lateral margin 20 and a second lateral edge 42 of the secondlateral margin 22.

The first and second lateral margins have a first end region 44extending from the first end edge 36 and a second end region 46extending from the second end edge 38. A central region 48 extendsbetween the first and second end regions. The central region 48 is thusbisected by the transverse axis T and it is this region that will formthe crotch portion of the completed garment. As such, the absorbentstructure 12 is located primarily or totally in the central region.Typically, the central region 48 may be between 20% and 70%, preferablybetween 30% and 60% of the extension of the chassis 14 in thelongitudinal direction.

In order to ensure an adequate fit and secure placement of the garmenton a wearer, the first and second lateral margins 20, 22 comprise afirst strip 49 and a second strip 50, respectively, of elastic material51. The first and second strips 49, 50 extend substantially parallel tothe longitudinal axis L from the first end edge 36 to the second endedge 38. The elastic material 51 is elastically extensible in at leastthe longitudinal direction in at least a portion of the central region48. Preferably, the material 51 is also elastically extensible in atleast a portion of, though preferably throughout, at least one of thefirst and second end regions 44, 46 in at least the transversedirection. In this manner, the elastic extensibility in the centralregion serves as leg elastic and the elastic extensibility in either orboth of the first and second end regions creates extensible side panels.To ensure an even distribution of forces, the material 51 may beelastically extensible in the longitudinal direction throughout thecentral region.

Given that leakage is often more prevalent though leg openings thanthrough the waist opening, in one embodiment of the invention theelastic extensibility in the longitudinal direction of the material 51in the central region 48 is at least 100% greater than the elasticextensibility in the transverse direction of the material 51 in eitheror both of the first and second end regions 44, 46, with the elasticextensibility in the longitudinal direction being from 90% to 350%,preferably from 150% to 300%, and most preferably from 200% to 250%.

In this respect, it is to be noted that reference to the percentage ofextensibility is indicative of the amount of extensibility over andabove the contracted length of the material. Thus, by way of example, ifa strip of material having a contracted length of 10.0 cm is extensibleby 90%, it will reach an extended length of 19.0 cm. Furthermore, whenused herein, the expression “elastic extensibility” implies that thematerial will undergo a plastic deformation of no more than 20%. Thus,for the example in which the 10.0 cm long strip of material is extendedby 90% to 19.0 cm, it will revert to a length of no more than 12.0 cmwhen the force causing the extension is removed.

Experiments conducted by the applicant have shown that, in order tocreate a good sealing effect around the leg openings of the garment, thematerial 51 of the first and second lateral margins 20, 22 can beselected such that a force of at least 40 cN, preferably at least 50 cN,most preferably about 60 cN, is required to cause the material in thecentral region to extend 75% of its maximum value of elasticextensibility in the longitudinal direction. In one embodiment accordingto the invention, the material 51 in the central region 48 has anavailable elongation of about 120% and a force of about 60 cN isrequired to extend the material 75% of this value.

As mentioned previously, the elastic extensibility in the first and/orsecond regions in the transverse direction need not be as great as thatof the elastic extensibility in the longitudinal direction in thecentral region and can be up to one half the elastic extensibility inthe longitudinal direction. In a further embodiment of the invention,the material is elastically extensible in the transverse direction inboth the first and second end regions. It is also conceivable that thematerial 51 be elastically extensible in the transverse direction andthe longitudinal direction in one or more of the central region 48 andthe first and second end regions 44, 46.

The material 51 may comprise various materials. As shown in FIG. 2, inone embodiment the material is an elastic web material in the form of anelastic laminate 52 comprising a first layer 54 of fibrous material andan elastic film layer 56. The elastic laminate may optionally include asecond layer 58 of fibrous material, with the elastic film layer beinglocated between the first and second layers of fibrous material. Howeverit is understood that other types of elastic web materials may be used,such as elastic nonwoven materials, nonwoven materials which per se areinelastic, but which have been elastified by suitable means, etc. Theelastic web materials may comprise one layer or two or more layers thathave been laminated.

In the elastic laminate shown and described below it is preferred thatthe first and second layers of fibrous material 54, 58 are chosen sothat they, in combination with the inner elastic film layer 56, give thematerial high resistance to puncture. They also provide a soft andcloth-like feel to the laminate. Examples of suitable materials arecarded webs and spunbond materials. The basis weight of the fibrousmaterial layers should be between 10 and 35 g/m², preferably between 12and 30 g/m², more preferably between 15 and 25 g/m². Examples ofsuitable polymers used in the fibrous materials are polyethylene,polyesters, polypropylene and other polyolefin homopolymers andcopolymers. Natural fibres, for example cotton, may also be used as longas they provide the required properties. A mixture of polymers cancontribute to a higher flexibility of the nonwoven layer, and in thisway, give the nonwoven material a higher elongation at maximum load. Amixture of polyethylene and polypropylene polymers has proved to providegood results in this respect. A mixture of fibers of different polymersis also possible.

The elastic film layer 56 may be constituted by an apertured elasticfilm having a basis weight between 20 and 80 g/m², preferably between 20and 60 g/m². The film may be of any suitable elastic polymer, natural orsynthetic. Some examples of suitable materials for the elastic film arelow crystallinity polyethylenes, metallocene-catalyzed low crystallinitypolyethylene, ethylene vinyl acetate copolymers (EVA), polyurethane,polyisoprene, butadiene-styrene copolymers, styrene block copolymers,such as styrene/isoprene/styrene (SIS), styrene/butadiene/styrene (SBS),or styrene/ethylene-butadiene/styrene block copolymer. Blends of thesepolymers may also be used as well as other modifying elastomeric ornon-elastomeric materials. One example of a suitable film is anapertured three-layer elastomeric film of PE-SEBS-PE.

For i.a. reasons of comfort, it is advantageous if the total basisweight of the laminate can be kept low. Thus, although a total basisweight of about 150 g/m² is acceptable, a total basis weight of 100 g/m²or less, for example no more than 90 g/m², is preferred.

The elastic laminate 52 may be manufactured according to the methoddisclosed in WO 03/047488, wherein one spunbond layer 54 is applied tothe film 56 in a tacky state and will thus bond to the film layer, whilethe other spunbond layer 58 is adhesively laminated to the film layer56, using for example a pressure sensitive hot melt adhesive.

The method disclosed in WO 03/047488 involves stretching of the laminateabove the point of failure of the fibrous material, so that thenon-elastic layers break completely. Therefore, as described in WO03/047488, the elongation of the laminate is not limited by the stretchmodulus of the non-elastic material.

Elasticity in both the longitudinal direction and the transversedirection may be imparted to the laminate in the manner disclosed in,for example, WO-A-95/04654.

To provide additional wearer comfort, the elastic laminate 52 may bebreathable and have a Water Vapour Transmission Rate according to ASTME96-00 of at least 1500 g/m²-24 h, preferably at least 3000 g/m²-24 h.

Bi-directionally elastically extensible material which may be adaptedfor use in the present invention is described in the art. Examplesinclude that which is disclosed in US-A1-2003/0105446, WO-A-95/29810,EP-A-0 432 763 and WO-A-95/32093, the contents of which are herebyincorporated by reference.

As is derivable from FIG. 2, the elastic material 51 of the first andsecond lateral margins may be substantially homogenous. By“substantially homogenous” it is meant that, irrespective of where inthe first and second strips 49, 50 material samples of 25 mm² surfacearea are taken through the thickness of the material, their compositionswill be effectively identical, i.e. it should not be possible toidentify a particular area having a composition which differs from anyother area. As a result, the material will display substantially thesame properties irrespective of where on the material samplemeasurements are made.

In the present invention, first and second lateral margins are providedin which only a part of the margins comprises the elastically extensiblematerial 51. Thus, in accordance with the present invention, and as isillustrated in FIG. 1, the first lateral edge 40 of the first lateralmargin 20 is provided by a third strip 76 of substantially inelasticmaterial joined to the first strip 49 of elastic material 51 along athird line of joinder 80. Similarly, the second lateral edge 42 of thesecond lateral margin 22 is provided by a fourth strip 78 ofsubstantially inelastic material joined to the second strip 50 ofelastic material along a fourth line of joinder 82. To facilitatemanufacturing, the third and fourth lines of joinder 80, 82 extendsubstantially parallel to the longitudinal axis (L).

As used herein, the expression “substantially inelastic material” refersto materials having an elastic extensibility of less than 20%,preferably less than 10%, more preferably less than 5%.

In accordance with a further aspect of the present invention, theinitial product can be adapted to serve as a garment by removing atleast a portion of the third and fourth strips 76, 78 of substantiallyinelastic material. Typical such portions are shown by cross-hatching inFIG. 1 and denoted by reference numbers 112, 113, respectively. Thus,the portions 112, 113 are removed from the central region 48 of thefirst and second lateral margins 20, 22. This implies that asubstantially inelastic first end patch 114, 116 of each of the thirdand fourth strips 76, 78 remains as a part of the lateral edge 40, 42 inthe first end region 44 and that a substantially inelastic second endpatch 118, 120 of each of the third and fourth strips 76, 78 remains asa part of the lateral edge 40, 42 in the second end region 44. Thesepatches of substantially inelastic material provide an ideal surface onwhich to affix, for example, fastening tabs and/or landing zones of agarment closure system. Alternatively, in the case of a pull-up typegarment, seams between side panels of the first and second end regionsmay be formed in the inelastic material. It is to be understood that theportions 112, 113 that are removed may also include an area of theelastic material 51.

To reduce the risk of the garment “bunching” in use, it may beadvantageous if the central structure 24 of the chassis is substantiallynon-elastic. By allowing the central structure to carry or support theabsorbent structure 12, the absorbent structure will not be directlysubjected to any tensile forces in use.

FIG. 3 is a highly schematic representation of a cross-section throughan initial product 10 according to one embodiment of the invention. Inthis embodiment, the absorbent structure 12 is carried by the centralstructure 24, the central structure being constituted by a backsheetlayer 60 and a topsheet layer 62, with the absorbent structure beingsandwiched therebetween. The backsheet layer is advantageously of aliquid impervious material such as a thin plastic film, e.g. apolyethylene or polypropylene film, a nonwoven material coated with aliquid impervious material, a hydrophobic nonwoven material whichresists liquid penetration or a laminate comprising plastic films andnonwoven materials. The backsheet layer 60 may be breathable so as toallow vapour to escape from the absorbent structure, while stillpreventing liquids from passing therethrough. Examples of breathablebacksheet materials are porous polymeric films, nonwoven laminates fromspunbond and meltblown layers, laminates from porous polymeric films andnonwovens.

The topsheet layer 62 is liquid permeable and can consist of a nonwovenmaterial, for example spunbond, meltblown, carded, hydroentangled,wetlaid, etc. Suitable nonwoven materials can be composed of naturalfibers, such as woodpulp or cotton fibres, manmade fibres, such aspolyester, polyethylene, polypropylene, viscose etc. or from a mixtureof natural and manmade fibres. The topsheet layer may further becomposed of tow fibres, which may be bonded to each other in a bondingpattern, as e.g. disclosed in EP-A-1 035 818. Further examples ofsuitable topsheet materials are porous foams, apertured plastic filmsetc. The materials suited as the topsheet layer should be soft andnon-irritating to the skin and intended to be readily penetrated by bodyfluid, e.g. urine or menstrual fluid. Any of the materials useful forthe topsheet layer may be used as the substantially inelastic materialof the third and fourth strips 76, 78.

The absorbent structure 12 can be of any conventional kind. Examples ofcommonly occurring absorbent materials are cellulosic fluff pulp, tissuelayers, highly absorbent polymers (so called superabsorbents), absorbentfoam materials, absorbent nonwoven materials or the like. It is commonto combine cellulosic fluff pulp with superabsorbents in an absorbentbody. It is also common to have absorbent bodies comprising layers ofdifferent material with different properties with respect to liquidreceiving capacity, liquid distribution capacity and storage capacity.The thin absorbent bodies, which are common in for example baby diapersand incontinence guards, often comprise a compressed mixed or layeredstructure of cellulosic fluff pulp and superabsorbent. The size andabsorbent capacity of the absorbent structure may be varied to be suitedfor different uses such as for infants or for incontinent adults.

The first and second lateral margins 20, 22 are joined to the centralstructure 24 along first and second lines of joinder 26, 28. Dependingon the various materials of the various components of the chassis, thelines of joinder may be of adhesive or created by ultrasonic welding. Asillustrated in FIG. 3, the first and second lateral margins 20, 22 arejoined to the topsheet layer 62 of the central structure. However, it isto be understood that the first and second lateral margins may be joinedto any suitable component of the central structure.

In accordance with the present invention, the first lateral edge 40 ofthe first lateral margin 20 of the initial product 10 is provided by athird strip 76 of substantially inelastic, e.g. nonwoven, materialjoined to the first strip 49 of elastic material 51 along a third lineof joinder 80. Similarly, the second lateral edge 42 of the secondlateral margin 22 is provided by a fourth strip 78 of substantiallyinelastic, e.g. nonwoven, material joined to the second strip 50 ofelastic material 51 along a fourth line of joinder 82. As explainedabove, in this manner, substantially non-elastic outer lateral edgeregions are provided which facilitate attachment of fastening tabs.Furthermore, the substantially non-elastic material provides for bettercontrol of the elastic material during production, as well as allowingfor a softer-feeling edge region on the finished product.

The garment illustrated in FIG. 3 further comprises so-called standinggathers 63 formed by fifth and sixth strips 64, 66 of substantiallyinelastic material. As is known per se, by providing the free end of thegathers with elastic threads 68, 70, barriers to the transmission ofbodily waste in the transverse direction are created. The material ofthe standing gathers may be the same as for the topsheet layer 62 or itmay be different. Purely by way of example, the topsheet may be aspunbond material and the standing gathers may be constituted by ameltblow material.

The optional standing gathers 63 may be formed by joining the fifthstrip 64 to the first strip 49 of elastic material along a fifth line ofjoinder 84 and by joining the sixth strip 66 to the second strip 50 ofelastic material along a sixth line of joinder 86. In FIG. 3, the fifthand sixth lines of joinder are illustrated as lying transverselyoutwardly of the first and second lines of joinder 26, 28, though it isto be understood that the fifth and sixth lines of joinder may betransversely inward of the first and second lines of joinder or, indeed,substantially coincident therewith. To further control movement of thestanding gathers 63 when the garment is in use, the fifth and sixthstrips 64, 66 may also be joined to the topsheet layer 62 transverselyinwardly of the fifth and sixth lines of joinder 84, 86 by means ofadditional lines of joinder 72, 74.

The backsheet layer 60 and the topsheet layer 62 may be joined to eachother by a peripherally extending region of joinder 87 which maycomprise adhesive, for example pressure-sensitive adhesive.

The latter initial product 10 may be manufactured in accordance with amethod schematically illustrated in FIG. 4. Absorbent structures 12 arecarried on the backsheet layer 60 in the direction of arrow A,corresponding to the machine direction, towards receiving equipment,generally denoted by 88, for receiving the constituent components of thegarment. Thus, the first and second strips 49, 50 of elastic material 51are fed under varying tension towards a first mating station 90 viavariable speed rollers 92 such that the first and second strips areextended by from 90% to 350%, preferably from 150% to 300% and mostpreferably from 200% to 250%, to thereby create the central regions 48of the lateral margins 20, 22 immediately prior to being joined to thethird and fourth strips 76, 78 of substantially inelastic material inthe first mating station 90. Since less elasticity in the longitudinaldirection is sought in the first and second end regions 44, 46 of thelateral margins, the tension is reduced immediately prior to theseregions being joined to the third and fourth strips. At the first matingstation, the first and second strips 49, 50 are joined to the third andfourth strips by means of e.g. ultrasonic welding provided by ultrasonicwelding equipment 94 which creates the third and fourth lines of joinder80, 82. At the same mating station, the fifth and sixth strips 64, 66 ofsubstantially inelastic material may also be attached to the side of thefirst and second strips 49, 50 remote from the third and fourth strips76, 78. Such attachment is effected by the lines of joinder denoted 84,86 in FIG. 3. In this manner, a pair of initial united structures 96made up of the first and second lateral margins 20, 22, i.e. comprisingthe first and second strips 49, 50 of elastic material, the standinggathers 63 and the third and fourth strips 76, 78 of substantiallyinelastic material, is produced.

At a second mating station 98, at least one component of the centralstructure 24 is joined to the pair of initial united structures 96 bymeans of e.g. ultrasonic welding provided by ultrasonic weldingequipment 100 which creates the first and second lines of joinder 26, 28shown in FIG. 3. The at least one component of the central structure 24may be the topsheet layer 62. Either prior to, simultaneous with orsubsequent to forming the first and second lines of joinder, theadditional lines of joinder 72, 74 between the standing gathers 63 andthe topsheet layer 62 are formed. Exiting the second mating station 98is a subsequent united structure 102 thereby made up of the topsheetlayer 62 and the first and second lateral margins 20, 22.

The subsequent united structure 102 forms an overlay package 103 and isthereafter fed towards the absorbent structure 12 and backsheet layer 60via a feed roll 104, for example of the constant speed type, and laidover the absorbent structure and backsheet layer. The overlay package103 is then joined to the backsheet layer 60 at a final mating station106 to thereby sandwich the absorbent structure between the topsheetlayer and the backsheet layer to form the initial product 10. As isexplained earlier, the topsheet layer 62 and the backsheet layer 60 arepreferably joined to each other by a peripherally extending region ofjoinder of adhesive material. Thus, the adhesive may be sprayed onto thebacksheet at a spraying station 108 upstream of the constant speed roll104 and activated at the final mating station 106 by means of pressurerolls 110 or the like.

The initial product 10 which emerges from the final mating station 106is transported in the machine direction to subsequent processingstations which may include a (not shown) station at which a portion 112,113 of the third and fourth strips 76, 78 of substantially inelasticmaterial are removed to thereby form the garment. Advantageously, theportions 112, 113 are removed from the central region 48 of the firstand second lateral margins 20, 22. It is to be understood that furtherprocessing stations which do not form a part of the present inventionand are therefore not described here in further detail may be provided.

Instead of ultrasonic welding, it is to be understood that adhesive maybe used at one or more of the mating stations described above inrelation to FIG. 4.

In an alternative embodiment, the at least one component of the centralstructure 24 may comprise the entire central structure, i.e. thetopsheet layer 62, the backsheet layer 60 and the absorbent structure 12therebetween. The act of joining the pair of initial united structures96 to the central structure 24 will create a subsequent united structure102 which corresponds to the initial product 10.

In the above, reference has been made to elastic materials and elasticproperties thereof. In the following, two test procedures will bedescribed for assessing the elastic properties of these materials in thelongitudinal direction and the transverse direction, respectively. Inboth procedures, a tensile tester, Lloyd LRX, able to perform cyclicmovements and equipped with a printer/plotter or software presentationis used.

Procedure for Determining Retraction Forces and Available Elongation inthe Longitudinal Direction: Definitions:

The total available elongation (T_(t)) is the elongation of the samplewhen it is stretched from unaffected and contracted state to fulllength. The available elongation is expressed in % of the length of theunaffected sample.

The retraction force P(X) is the elastic force in the sample when it isstretched to an available elongation of X %.

Apparatus:

-   -   Tensile tester with cross head speed of 500 mm/min and 10 N        cell;    -   “Gate” for stretching the sample (denoted 122 in FIG. 5);    -   Butterfly clip with an appropriate weight for effecting desired        elongation of the sample, accuracy ±1 g;    -   Pen and scissors;    -   Ruler, accuracy ±0.3 mm;    -   Timer, accuracy ±0.3 s.

Sample Preparation:

-   -   Cut out the first and second lateral margins 20, 22 from the        product. Leave about 10 mm of the central structure 24 inward of        the first and second lines of joinder 26, 28;    -   If the product has third and fourth strips 76, 78 forming outer        lateral edge regions, these should be retained on the sample;    -   Remove any pulp from the central structure;    -   Fasten one end of the lateral margin in the gate clamp 124 and        fasten the butterfly clamp with weight to the other end. The        sample should be fully stretched without overstretching;    -   Let the weight hang freely for 15±5 s with the gate open. Close        the gate and mark the distance 200 mm (or 100 mm if 200 mm is        not possible);    -   Loosen the sample;    -   Allow the sample to rest for at least 30 minutes before        continuing the procedure.

Procedure:

-   -   Set the distance between the clamps of the tensile tester to 50        mm (or 25 mm if 100 mm was marked in the gate);    -   Calibrate the tensile tester, i.e. set to zero;    -   Fasten the sample in the clamps so that the marks from the gate        are just visible;    -   If the tensile tester is zeroed at the clamping length 50 mm,        the sample is cycled to “max limit” 148 mm, corresponding to a        clamping length of 198 mm (corresponding “max limit” 73 mm if        set to zero at 25 mm);    -   Start the tensile tester;    -   Let the tensile tester carry out three cycles.

Calculations and Expression of Results:

See FIG. 6.

-   L₀=The distance from the start point of the graph to the point on    the third retraction curve where the force is equal to zero plus 50    mm (or 25 mm for the short length);-   L=The length used in the gate, 198 mm (or 98 mm);-   A_(X)=The distance to the point where the retraction force P(X) is    read;-   X=The available elongation in primary form, e.g. 20% available    elongation is 1.20.

Available elongation is calculated from the formula:

T _(t)=100×(L−L ₀)/L ₀

The retraction force is read from the third retraction curve atrespectively available elongation according to:

A _(X) =L/X

The accuracy of the results is stated on available elongation in % bywhole numbers ±10%, and retraction force P(X) in cN by whole numbers.

Procedure for Determining Retraction Forces and Available Elongation inthe Transverse Direction:

The purpose of this procedure is to determine how an elastic materialbehaves at repeated load and unload cycles.

Definition:

Permanent elongation is defined as the extension of the material afterit has been exposed to a repeated elongation and relaxation.

Principle:

The sample is stretched to a predetermined elongation. A cyclic movementbetween 0 and the predetermined elongation is performed. Desired loadand unload forces are recorded. The permanent, i.e. remaining,elongation of the relaxed sample is measured.

Apparatus:

-   -   Scalpel;    -   Ruler, accuracy ±0.3 mm;    -   Pen (waterproof);    -   Tape;    -   Tensile tester with cross head speed of 500 mm/min and 10 N        cell.

Sample Preparation:

-   -   The sample is prepared by cutting it to a width of 25 mm and a        length that is preferably 20 mm longer than the distance between        the clamps in the tensile tester;    -   To reduce slipping, mark the clamp distance, 50 mm, on the        sample and put tape on the marks.

Procedure:

-   -   Calibrate the tensile tester;    -   Set the required parameters, i.e. cross head speed of 500        mm/min, clamp distance of 50 mm and preload of 0.05 N;    -   Place the sample in the clamps according to the marks and ensure        that the sample is centered and fastened perpendicularly to the        clamps;        Start the tensile tester;    -   Perform the predetermined number of cycles between 0 and the        predetermined elongation, equal to the highest defined 1^(st)        load force;    -   Before the last cycle, relax the sample for one minute then        measure the permanent elongation by stretching the sample until        a force of 0.1 N is detected and read the elongation.

Calculation and Expression of Results:

Desired load and unload forces are recorded. The permanent, i.e.remaining, elongation of the relaxed material is measured.

The accuracy of the results is stated to 1 decimal of values in N and inwhole numbers of values in %.

The permanent elongation after relaxation of the elastic material 51intended to be used in the present invention should be no more than 20%and is measured by the method above. Thus an elasticity of 90% isdefined as that the laminate should have a permanent relaxation afterelongation of no more than 20% after being exerted to an elongation of90% in the tensile tester above. As explained previously, an elongationof 90% means an elongation to a length that is 90% longer than theinitial length of the sample.

The invention has been described in the above by way of example only andvarious modifications will be apparent to the skilled person. Forexample, although the initial product according to the invention hasbeen described having an integrated absorbent structure, it is to beunderstood that the initial product may instead be manufactured with apocket for receiving a replaceable absorbent structure. Accordingly, itis to be understood that the scope and limitations of the invention aredefined solely by the appended claims.

1. An initial product adaptable to serve as a garment for receiving anabsorbent structure, said garment adapted to be worn around the waist ofa user, said initial product comprising: a chassis for receiving saidabsorbent structure, said chassis extending in a longitudinal directionabout longitudinal axis dividing the chassis into a first lateral halfand a second lateral half, said first lateral half comprising a firstlateral margin and said second lateral half comprising a second lateralmargin, said first and second lateral margins being joined to a centralstructure along a first line of joinder and a second line of joinder,respectively, said first and second lines of joinder extendingsubstantially parallel to said longitudinal axis, said chassis furtherextending in a transverse direction about a transverse axis dividing thechassis into a first end and a second end, said chassis being delimitedby a periphery comprising a first end edge at said first end and asecond end edge at said second end, said first and second end edgesextending substantially parallel to said transverse axis, said peripheryfurther comprising a first lateral edge of said first lateral margin anda second lateral edge of said second lateral margin, said first andsecond lateral margins having a first end region extending from saidfirst end edge, a second end region extending from said second end edgeand a central region extending between said first and second endregions, said first and second lateral margins comprising a first stripand a second strip, respectively, of elastic material extending fromsaid first end edge to said second end edge, which material iselastically extensible in at least said longitudinal direction in atleast a portion of said central region, said first lateral edge of saidfirst lateral margin being provided by a third strip of substantiallyinelastic material joined to said first strip of elastic material alonga third line of joinder and said second lateral edge of said secondlateral margin being provided by a fourth strip of substantiallyinelastic material joined to said second strip of elastic material alonga fourth line of joinder, said third and fourth lines of joinderextending substantially parallel to said longitudinal axis.
 2. Theinitial product as claimed in claim 1, wherein said first and secondlateral margins further comprise a fifth strip and a sixth strip,respectively, of substantially inelastic material joined to said firststrip and said second strip, respectively, of elastic material alongfifth and sixth lines of joinder, respectively, extending substantiallyparallel to said longitudinal axis, said fifth and sixth strips beingjoined to said first and second strips along edges remote from saidthird and fourth strips such that, when serving as a garment, said fifthand sixth strips serve as standing gathers.
 3. The initial product asclaimed in claim 1, wherein said elastic material is elasticallyextensible in at least a portion of at least one of said first andsecond end regions in at least said transverse direction.
 4. The initialproduct as claimed in claim 3, wherein the elastic extensibility in saidlongitudinal direction of said elastic material in said at least aportion of said central region is at least 100% greater than the elasticextensibility in said transverse direction of said material in said atleast a portion of said at least one of said first and second endregions.
 5. The initial product as claimed in claim 3, wherein theelastic extensibility in said longitudinal direction of said elasticmaterial in said central region is from 90% to 350%.
 6. The initialproduct as claimed in claim 1, wherein the elastic material of the firstand second lateral margins is selected such that in use a force of atleast 20 cN is required to cause the material in said central region toextend 75% of its maximum value of elastic extensibility in saidlongitudinal direction.
 7. The initial product as claimed in claim 6,wherein the elastic material in said central region has an availableelongation of at least 120% and a force of about 60 cN is required toextend the material 75% of this value.
 8. The initial product as claimedin claim 3, wherein the elastic material is elastically extensible insaid transverse direction in both said first and second end regions. 9.The initial product as claimed in claim 3, wherein the elastic materialis elastically extensible in said transverse direction and saidlongitudinal direction in one or more of said central region and saidfirst and second end regions.
 10. The initial product as claimed inclaim 1, wherein the elastic material is an elastic nonwoven material oran elastic laminate comprising a first layer of elastic or non-elasticfibrous material and an elastic film layer.
 11. The initial product asclaimed in claim 10, wherein the elastic laminate is composed of saidfirst layer of fibrous material, a second layer of fibrous material andsaid elastic film layer is located between said first and second layersof fibrous material.
 12. The initial product as claimed in claim 10,wherein the first and/or the second layers of fibrous material comprisea mixture of polypropylene and polyethylene polymers.
 13. The initialproduct as claimed in claim 10, wherein said elastic laminate (52)comprises first and second fibrous layers of spunbond material, eachhaving a basis weight of between 10 and 35 g/m² and an elastic filmlayer having a basis weight of between 20 and 80 g/m².
 14. The initialproduct as claimed in claim 1, wherein said elastic material isbreathable and has a Water Vapour Transmission Rate according to ASTME96-00 of at least 1500 g/m²-24 h.
 15. The initial product as claimed inclaim 1, wherein said elastic material is substantially homogenous. 16.The initial product as claimed in claim 2, wherein said third, fourth,fifth and sixth strips of substantially inelastic material are ofnonwoven material.
 17. The initial product as claimed in claim 1,wherein said central structure of said chassis is substantiallynon-elastic.
 18. The initial product as claimed in claim 17, whereinsaid central structure carries said absorbent structure.
 19. The initialproduct as claimed in claim 18, wherein said central structure comprisesa backsheet layer and a topsheet layer, said absorbent structure beingsandwiched therebetween.
 20. A garment for receiving an absorbentstructure, said garment adapted to be worn around the waist of a user,said garment being constituted by the initial product as claimed inclaim 1, in which at least a portion of said third and fourth strips ofsubstantially inelastic material has been removed.
 21. The garment asclaimed in claim 20, wherein said at least a portion is removed fromsaid central region of said first and second lateral margins.
 22. Amethod of manufacturing an initial product adaptable to serve as agarment for receiving an absorbent structure, said garment adapted to beworn around the waist of a user, said initial product comprising achassis for receiving said absorbent structure, said chassis comprisinga central structure comprising a topsheet layer and a backsheet layer,as well as first and second lateral margins joined to said centralstructure along first and second lines of joinder, respectively, themethod comprising the steps of: providing first and second strips ofmaterial which are or are adapted to be made elastically extensible inat least the machine direction, said first and second strips serving asfirst and second strips of elastic material of the first and secondlateral margins of the initial product; feeding the first and secondstrips under varying tension towards a first mating station via variablespeed rollers; providing third and fourth strips of substantiallyinelastic material for constituting first and second lateral edges ofthe initial product and feeding said third and fourth strips to saidfirst mating station; joining said third and fourth strips to said firstand second strips at said first mating station by third and fourth linesof joinder to produce a pair of initial united structures; advancingsaid pair of initial united structures to a second mating station;providing at least one component of said central structure and feedingsaid at least one component towards said second mating station, andjoining said at least one component to said pair of initial unitedstructures at said second mating station by said first and second linesof joinder to produce a subsequent united structure.
 23. The method asclaimed in claim 22, wherein said step of providing third and fourthstrips of substantially inelastic material further comprises providingfifth and sixth strips of substantially inelastic material, and saidstep of joining said third and fourth strips to said first and secondstrips (49, 50) further comprises joining said fifth and sixth strips tosaid first and second strips along edges of said first and second stripsremote from said third and fourth strips by fifth and sixth lines ofjoinder.
 24. The method as claimed in claim 22, wherein said at leastone component of said central structure is said topsheet layer.
 25. Themethod as claimed in claim 24, wherein said subsequent united structureis in the form of an overlay package, the method further comprising thestep of feeding said overlay package towards a third mating station atwhich said overlay package is joined to said backsheet layer of saidchassis.
 26. The method as claimed in claim 22, wherein said first andsecond strips are fed under varying tension towards said first matingstation via variable speed rollers such that said first and secondstrips are extended by from 90% to 350% and said first and second stripsare joined to said third and fourth strips when so extended.
 27. Themethod as claimed in claim 26, wherein said first and second strips arealso joined to said fifth and sixth strips when so extended.
 28. Themethod as claimed in claim 25, wherein the step of feeding said overlaypackage towards a third mating station is effected via a constant speedroll.
 29. The method as claimed in claim 25, wherein at said thirdmating station said absorbent structure is integrated between saidtopsheet layer and said backsheet layer.
 30. The method as claimed inclaim 22, wherein said lines of joinder are created by ultrasonicwelding equipment.
 31. The method as claimed in claim 22, wherein saidmethod includes the subsequent step of removing at least a portion ofsaid third and fourth strips of substantially inelastic material tothereby form said garment.
 32. The method as claimed in claim 31,wherein said at least a portion is removed from said central region ofsaid first and second lateral margins.